Chung-Wei Lin

A Predictive Video-on-Demand Bandwidth Management Using the Kalman Filter over Heterogeneous Networks

In order to adapt the quality of an on-demand video stream over a time-varying bandwidth channel, a network-aware bandwidth estimation and rate control scheme are required. This paper proposes a predictive video-on-demand (VoD) bandwidth management and a feedback-based buffer control scheme for streaming fine granular scalability videos over wired/WLAN/3G networks. The predictive VoD bandwidth management includes two parts: bandwidth estimation and rate adaptation. According to the measured information of packet round-trip-time, loss-rate, delay jitter and received bit-rate, an improved Kalman filter is proposed to predict an available bandwidth recursively, and to determine a proper transmission rate in consideration of buffer fullness of a decoder. The optimal parameters of the Kalman filter, e.g. a transition matrix and error covariances, can be initialized, converged and adapted to characteristics of the current network. In our experiments, distinct network traffic models are simulated in comparison with pathChirp and one Republic of China patent. The corresponding estimation results with respect to network information are also exhibited in the real networks.

A Multilayered Audiovisual Streaming System Using the Network Bandwidth Adaptation and the Two-Phase Synchronization

Synchronous audiovisual streaming and playout are two of the major issues in the multimedia communication network. However, the past corresponding researches of media synchronization mainly focused on the mono-quality and single-layer (nonscalable) audiovisual data. To overcome challenges of ubiquitous multimedia streaming, a scalable audiovisual coder that can provide flexible scalabilities and adaptive streaming control to adapt to complicated network situations are both required. This paper proposes a multilayered audiovisual streaming scheme to deliver layered audiovisual data synchronously, which is called ML-AVSS. Fine-granular scalability (FGS) and bit-sliced arithmetic coding (BSAC) techniques are used to segment video and audio data into one base-layer and multiple enhancement-layer bitstreams. With advantages of audiovisual layer coding, a de-jitter procedure, a conditional retransmission mechanism and a playout synchronization mechanism are designed to transmit hybrid multilayered audiovisual bitstreams in consideration of the result of a network bandwidth adaptation and the distinct decoding time-complexity. Experimental results show that the proposed ML-AVSS is a feasible streaming scheme to overcome challenges of ubiquitous multimedia streaming, e.g., constrained channel bandwidth, quality degradation, unsmooth playout, etc.

A Novel 4-D Perceptual Quantization Modeling for H.264 Bit-Rate Control

Bit-rate control plays a major role In video coding and multimedia streaming. A well-designed bit-rate control mechanism can achieve line visual qualities and avoid network congestion over a time-varying channel. This paper proposes an H.264 bit-rate control using a 4D perceptual quantization modeling (PQrc), including two major encoding modules: the perceptual frame-level bit-allocation using a 1D temporal pattern and the macroblock-level quantizer decision using a 3D rate pattern. The temporal pattern is used to predict frame complexity and determine proper budget bits further. The rate pattern is depicted as a bit-complexity-quantization (B.C.Q.) model, in which a tangent slope of a B.C.Q. curve is a piece of unique information to find a proper quantizer. For newly generated video clips, the B.C.Q. model is updated continuously using a weighted least-square estimation. In comparison with the latest H.264 JM10.2, our experiment results show that the proposed PQrc can: 1) keep stable buffer fullness and 2) improve the SNR quality and control accuracy effectively.

Mobility Management for Video Streaming on Heterogeneous Networks

This article discusses how ubiquitous video streaming platform can let people enjoy continuous multimedia services at any time, in any location, and with any computing device. There are several technical challenges to be met in the process of achieving this goal. These challenges entail developing sophisticated session handoff control, session descriptions, communication signaling, and adaptive video streaming, among other factors.

Network-Aware Multimedia Streaming using the Kalman Filter Over the Wired/Wireless/3G Networks

In order to adapt the quality of videos streamed over a time-varying bandwidth channel, a network-aware bandwidth management and rate control are required. This paper proposes the well-designed bandwidth estimation and active buffer control for streaming H.264 FGS videos over heterogeneous wired/ wireless/3G networks. According to the information of measured packet round-trip-time, loss-rate and delay jitter, an improved Kalman filter is proposed to predict the throughput recursively, and determine the transmission rate in consideration of buffer fullness of a decoder. The optimal parameters of the Kalman filter, e.g., transition matrix and error covariance, can be initialized, converged and adapted to the current network, even when the session handoff occurs. In our real experiments, distinct network traffic models are simulated, and corresponding estimation results w.r.t. network information are also exhibited.

An SVC-MDC video coding scheme using the multi-core parallel programming paradigm for P2P video streaming

In this paper, we propose a COmbined SVC-MDC (Scalable Video Coding & Multiple Description Coding) video coding scheme using the multi-core parallel programming paradigm for P2P video streaming, which is denoted Co-SVC-MDC. To date, P2P video streaming applications are widely popular and emphasized, e.g., PPstream and PPlive, because of higher transmission speed and data availability. However, in the heterogeneous P2P network environment, users are able to utilize PDA, notebook or desktop computer through distinct network interfaces to get on-demand videos ubiquitously. To provide distinct spatial-resolution/fidelity videos and flexible video transmission (playback) over P2P networks, a brand new coding architecture needs to be devised. In the proposed Co-SVC-MDC coding scheme, distinct MDC descriptions contain distinct portions of raw video frames, and each raw frame can be compressed as base layer and SVC enhancement layers. In our experiments, a real implementation of Co-SVC-MDC is exhibited and corresponding performances, e.g., PSNR and decoding speeds, are compared with original SVC in distinct congestion-level P2P networks.

A hybrid spatial-temporal fine granular scalable coding for adaptive QoS Internet video

In a ubiquitous multimedia space, a video streaming service is requested to be continuous and uninterrupted even if a client may change her/his client device, network link and preferences at any time and anywhere. Thus, a video coder that can provide more wide range quality-of-service (QoS) and more flexible control is urgently required. This paper presents a hybrid coder structure that integrates spatial-, temporal- and SNR-scalabilities to handle MPEG-4 videos. Using the proposed hybrid coder, different presentation qualities, including spatial-temporal resolution and SNR quality, can be rendered when frames are decoded from the base-layer (BL) and partial enhancement-layer (EL) sub-bitstreams. Besides, a refined rate-adaptation approach in the MPEG-4 FGS scheme and a buffer control mechanism are also devised to increase the bandwidth utilization and to prevent buffer instability. According to the experiments results, the proposed hybrid coder shows outperformances over classic non-scalable MPEG-2 and MPEG-4 FGS coder in consideration of the flexible QoS for Internet video streaming.

Metal dusting of pre-carburised 304L stainless steel

Abstract The metal dusting behaviour of 304L stainless steel (SS) with or without precarburisation treatment was investigated in a flowing CO/CO2 atmosphere at the temperature range of 500–700°C. A thermogravimetric analyser was used to conduct the short term (30 h) exposure tests, while a tube furnace was employed for the prolonged (500 h) tests. The relative resistance to metal dusting and the morphological aspects of the steel with three different surface conditions were compared and examined. The experimental results showed localised attack resulting from metal dusting was found on the surface of the as carburised 304L SS, while it became more uniformly attacked by removing the surface scale formed in pack carburising process before exposure in the CO/CO2 mixed gas. In a sufficient high carbon activity gas atmosphere, the susceptibility to metal dusting of the as carburised 304L SS increased with increasing temperature.

A Multiple Layered Audiovisual Streaming System Using the Two-Phase Synchronization and FGS/BSAC Techniques

For a ubiquitous multimedia streaming, an adaptive multimedia streaming scheme with multiple layered audiovisual (AV) coding is required over heterogeneous networks. This paper proposes a multiple layered audiovisual streaming scheme denoted ML-AVSS to deliver layered audiovisual data. Fine-granular scalability (FGS) and bit sliced arithmetic coding (BSAC) techniques are used to segment video and audio data into individual base-layer and multiple enhancement-layer bitstreams. With advantages of layered coding, two phases of streaming synchronization, including a human-perceptual based transmission scheme, de-jitter procedure, conditional retransmission and play- out synchronization, are proposed to transmit hybrid multiple layered audiovisual bitstreams. Experiment results show that the proposed ML-AVSS is a feasible streaming scheme to overcome challenges of the ubiquitous multimedia streaming, e.g., constrained available bandwidth, quality degradation, unsmooth playback, etc.

Error-robust scalable extension of H.264/AVC ubiquitous streaming using the adaptive packet interleaving mechanism

In this article, we realize error-robust scalable extension of H.264/AVC video streaming using an adaptive packet interleaving mechanism among heterogeneous networks and devices. The state-of-the-art SVC was used to provide combined scalability to adjust spatiotemporal resolutions and SNR quality. In an error-prone channel, a method of bandwidth estimation and a three-state network transition chain are proposed to adjust the transmission bit-rate and the interleaving window size, respectively. Unlike past packet interleaving methods, the interleaving window size can be adjusted dynamically to compromise pre-processing delay, e.g., packet rearrangement time for interleaving, and quality improvement. Additionally, with the understanding of the global SVC bitstream structure, an SVC coder was designed to increase the decoding efficiency and extract in real time the proper SVC-quality bitstream based on the network condition. In our experiments, performances of the adaptive packet interleaving mechanism w.r.t. distinct interleaving window sizes and network conditions are demonstrated for distinct kinds of videos.